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Serum Creatinine Concentration (Mass Concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood. It helps assess how well your kidneys are filtering blood.

Quick summary

["A creatinine test checks kidney function by tracking waste removal."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
24839-3
Short code
MR Neck
Synonyms
MR Neck
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
3.5
Ref high
5
Critical range
2.5 N/A – 6.5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
CPT
84132
SNOMED
110742001
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters

Your kidneys filter waste products, including creatinine, from your blood. High levels may indicate reduced kidney function or damage, while low levels could suggest overhydration or muscle loss. This test is often used alongside other kidney function tests to monitor chronic conditions like diabetes or hypertension.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader kidney function panel. Drink plenty of water the day before to ensure accurate results.

What to Expect During the Test

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it usually takes only a few minutes. The test itself is quick and painless.

What the Results Mean

Results are compared to a baseline or previous tests to track trends. While reference ranges vary by lab, consistently high or low values may signal kidney issues or other health concerns that need further evaluation.

Reference range

Adult: 3.5-5.0 mmol/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

How often should I get this test?
Your doctor will determine how often to check your creatinine levels based on your health history, medications, and any kidney-related conditions. For example, people with diabetes or kidney disease may need tests more frequently.
What can affect my creatinine levels?
Several factors can influence creatinine levels, including muscle mass (higher muscle mass can raise levels), dehydration, or certain medications. If you’ve had recent changes in activity, diet, or hydration, let your provider know.
Do I need to do anything special after the test?
No special actions are required after the blood draw. If you experience bruising or discomfort, apply gentle pressure to the site. Follow up with your doctor if you have concerns about your results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy